Hybrid fixation features for three-dimensional porous structures for bone ingrowth and methods for producing

ABSTRACT

An orthopaedic prosthetic component comprises a fixation peg including a porous three-dimensional structure configured to permit bone in-growth. The porous three-dimensional structure has an outer surface boundary. The fixation peg includes a plate attached to the porous three-dimensional structure at the outer surface boundary. The plate includes a tapered body having an outer wall that faces away from the porous three-dimensional structure and is devoid of any openings.

This is a continuation of U.S. patent application Ser. No. 16/370,599,which was filed on Mar. 29, 2019, which claims priority to U.S.Provisional App. No. 62/650,790, which was filed on Mar. 30, 2018, eachof which is expressly incorporated herein by reference.

TECHNICAL FIELD

The embodiments disclosed herein are generally directed towards porousmetal structures and methods for manufacturing them, and, morespecifically, to porous metal structures in medical devices.

BACKGROUND

The embodiments disclosed herein are generally directed towards surfacefeatures for three-dimensional porous structures for bone ingrowth andmethods for producing said structures.

The field of rapid prototyping and additive manufacturing has seen manyadvances over the years, particularly for rapid prototyping of articlessuch as prototype parts and mold dies. These advances have reducedfabrication cost and time, while increasing accuracy of the finishedproduct, versus conventional machining processes, such as those wherematerials (e.g., metal) start as a block of material, and areconsequently machined down to the finished product.

However, the main focus of rapid prototyping three-dimensionalstructures has been on increasing density of rapid prototypedstructures. Examples of modern rapid prototyping/additive manufacturingtechniques include sheet lamination, adhesion bonding, laser sintering(or selective laser sintering), laser melting (or selective lasersintering), photopolymerization, droplet deposition, stereolithography,3D printing, fused deposition modeling, and 3D plotting. Particularly inthe areas of selective laser sintering, selective laser melting and 3Dprinting, the improvement in the production of high density parts hasmade those techniques useful in designing and accurately producingarticles such as highly dense metal parts.

In the field of tissue engineering, a porous three-dimensionalbiocompatible scaffold is needed to accommodate mammalian cells andpromote their three-dimensional growth and regeneration, and thus can beused for example, as implants/prosthetic components or other prostheses.Furthermore, this scaffold, or ingrowth coating, requires sufficientsurface texture to promote stable implant-bone interface essential forrapid and effective bone ingrowth. Fixation features (e.g., pegs) withhigher fixation strength limit, for example, the implant-to-bone motionand increase opportunity for bony in-growth more than pegs that are notwell fixated in the bone.

SUMMARY

According to one aspect of the disclosure, an orthopaedic prostheticcomponent is disclosed. The orthopaedic prosthetic component comprises abase and a fixation peg extending away from the base to a distal tip.The fixation peg includes a porous three-dimensional structureconfigured to permit bone in-growth”, and the porous three-dimensionalstructure has an outer surface boundary. The fixation peg includes aplurality of plates attached to the porous three-dimensional structureat the outer surface boundary. Each plate includes a tapered body havingan outer wall that faces away from the porous three-dimensionalstructure and is devoid of any openings.

In some embodiments, the tapered body of each plate may extendlongitudinally along the porous three-dimensional structure.Additionally, in some embodiments, the tapered body of each plate mayextend from a proximal end to a distal end, and the tapered body of eachplate may have a first width at the proximal end and a second widthgreater than the first width between the proximal end and the distalend.

In some embodiments, the outer wall of each plate may include a concavesurface that defines a tapered channel. In some embodiments, each plateis a solid plate that is devoid of any openings or through-holes.

In some embodiments, the plurality of plates may be arrangedcircumferentially on the porous three-dimensional structure.Additionally, in some embodiments, adjacent plates of the plurality ofplates may be spaced apart circumferentially from each other on theporous three-dimensional structure.

In some embodiments, the plurality of plates may be positioned betweenthe distal tip of the fixation peg and the base. Additionally, in someembodiments, the base may include a tibial platform configured toreceive a tibial insert. In some embodiments, an elongated stem mayextend from the tibial platform to a distal tip. The elongated stem maybe configured to be implanted in a surgically-prepared proximal end of apatient's tibia.

In some embodiments, the orthopaedic prosthetic component may furthercomprise a porous three-dimensional layer attached to a distal surfaceof the tibial platform. The elongated stem may extend outwardly from thethree-dimensional layer, and the fixation peg extends outwardly from theporous three-dimensional layer.

In some embodiments, the tapered body of each plate may extend from aproximal end to a distal end, and the tapered body of each plate mayhave a first thickness at the distal end and a second thickness greaterthan the first thickness between the proximal end and the distal end.

In some embodiments, each plate may extend circumferentially around theporous three-dimensional structure. Additionally, in some embodiments,adjacent plates of the plurality of plates may be spaced apart from eachother on the porous three-dimensional structure in a proximal-distaldirection. In some embodiments, the distal tip of the fixation peg mayinclude a longitudinal slot.

According to another aspect, an orthopaedic prosthetic componentcomprises a tibial platform configured to receive a tibial insert and aporous three-dimensional structure coupled to the tibial platform. Theporous three-dimensional structure is configured to permit bonein-growth. The orthopaedic prosthetic component also comprises anelongated stem extending away from the tibial platform to a distal tip.The porous three-dimensional structure includes a layer coupled to thetibial platform and a plurality of fixation pegs extending from thelayer. Each fixation peg includes a portion of the porousthree-dimensional structure that has an outer surface boundary. Aplurality of plates are attached at the outer surface boundary of eachfixation peg. Each plate includes a tapered body having an outer wallthat is devoid of any openings.

In some embodiments, the tapered body of each plate may extendlongitudinally along the porous three-dimensional structure.Additionally, in some embodiments, the outer wall of each plate mayinclude a concave surface that defines a tapered channel.

In some embodiments, adjacent plates of the plurality of plates may bespaced apart circumferentially from each other on each peg. In someembodiments, adjacent plates of the plurality of plates may be spacedapart from each other on the porous three-dimensional structure in aproximal-distal direction.

According to another aspect, a method for producing an orthopaedicprosthetic component is disclosed. The method comprises depositing andscanning successive layers of metal powders to form a porousthree-dimensional structure comprising at least one fixation peg. The atleast one fixation peg comprises a porous portion and at least one solidplate positioned on the porous portion.

According to yet another aspect, an orthopaedic implant is disclosed.The implant comprises a porous three-dimensional structure and at leastone fixation feature extending past a surface boundary of the porousthree-dimensional structure. The porous three-dimensional structure iscomprised of a plurality of unit cells. The fixation feature is anchoredto a first side of the porous three-dimensional structure and iscomprised of a porous portion and a plurality of solid portionspositioned on an outside surface of the porous portion.

In some embodiments, the implant further comprises a base that isanchored to a second side of the porous three-dimensional structure.

In some embodiments, the fixation feature is further comprised of alength that is greater than a width.

In some embodiments, the fixation feature is further comprised of awidth that is greater than a length.

In some embodiments, the plurality of solid portions extend outwardlyfrom the surface boundary of the porous three-dimensional structure.

In some embodiments, the plurality of solid portions are positionedsubstantially parallel to the surface boundary of the porousthree-dimensional structure.

In some embodiments, the fixation feature is further comprised of aporous tip portion distal to the porous three-dimensional structure.

In some embodiment, the implant is further comprised of a plurality offixation features.

In some embodiments, the porous portion further includes a plurality ofscallops. In some embodiments, each of the plurality of solid portionsoccupy a respective scallop. In some embodiments, each of the pluralityof scallops is comprised of a distal region that is larger than aproximal region.

In some embodiments, at least one of the plurality of solid portions isattached to a porous portion. In some embodiments, the plurality ofsolid portions tapers in the distal direction. In some embodiments, eachof the plurality of solid portions is attached to a porous portion. Insome embodiments, each of the plurality of solid portions tapers in adistal direction. In some embodiments, the thickness of each respectivesolid portion is less than the solid portion immediately proximal.

In another aspect, an orthopaedic implant is disclosed. The implantcomprises a porous three-dimensional structure including at least onefixation feature. The one fixation feature comprises a porous portionhaving an interior, at least one solid portion and at least one slotthat is partially located on the interior of the porous portion.

In some embodiments, the at least one solid portion is positioned on anoutside surface of the porous portion.

In some embodiments, the implant is further comprised of a base that isanchored to a second side of the porous three-dimensional structure.

In some embodiments, the fixation feature is comprised of a width thatis greater than the length.

In some embodiments, the fixation feature is comprised of a length thatis greater than the width.

In some embodiments, the at least one solid portion is positionedsubstantially perpendicular to the surface boundary of the porousthree-dimensional structure.

In some embodiments, the at least one solid portion extends to a tipregion of the at least one fixation feature that is distal to the porousthree-dimensional structure.

In some embodiments, the implant is further comprised of a plurality offixation features.

In some embodiments, the at least one solid portion includes at leastone barb that tapers in the distal direction. In some embodiments, theat least one solid portion includes a plurality of barbs. In someembodiments, the thickness of each respective barb is less than the barbimmediately proximal.

In some embodiments, the at least one solid portion is attached to theporous portion.

In some embodiments, the at least one solid portion tapers in the distaldirection.

In some embodiments, the implant is comprised of a plurality of solidportions. In some embodiments, each of the plurality of solid portionsattaches to the porous portion. In some embodiments, each of theplurality of solid portions tapers in the distal direction. In someembodiments, each of the plurality of solid portions includes at leastone barb that tapers in the distal direction.

In some embodiments, the at least one slot provides an opening at a tipregion of the at least one fixation feature.

In some embodiments, the implant is comprised of a plurality of slots.

In another aspect, a method for producing an orthopaedic implant isdisclosed. The method comprises depositing and scanning successivelayers of metal powders to form a porous three-dimensional structurecomprising a plurality of unit cells and to form at least one fixationfeature that extends beyond a surface boundary of the porousthree-dimensional structure. The at least one fixation feature isanchored to a first side of the porous three-dimensional structure andis comprised of a porous portion having an interior, at least one solidportion and at least one slot at least partially located on the interiorof the porous portion.

In some embodiments, the method further comprises providing a base andanchoring a second side of the porous three-dimensional structure to thebase.

In yet another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises depositing and scanningsuccessive layers of metal powders with a beam to form a porousthree-dimensional structure comprising a plurality of unit cells and toform at least one fixation feature that extends beyond a surfaceboundary of the porous three-dimensional structure. The at least onefixation feature is anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion.

In some embodiments, the method further comprises providing a base andanchoring a second side of the porous three-dimensional structure to thebase.

In some embodiments, the beam is an electron beam.

In some embodiments, the beam is a laser beam.

In some embodiments, the metal powders are melted to form the porousthree-dimensional structure.

In some embodiments, the metal powders are sintered to form the porousthree-dimensional structure.

In some embodiments, the successive layers of metal powders aredeposited onto a solid base.

In another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises applying a stream of metalparticles at a predetermined velocity onto a base to form a porousthree-dimensional structure and to form at least one fixation featurethat extends beyond a surface boundary of the porous three-dimensionalstructure. The porous three-dimensional structure is comprised of aplurality of unit cells. The fixation feature is anchored to a firstside of the porous three-dimensional structure and is comprised of aporous portion and a plurality of solid portions positioned on anoutside surface of the porous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In some embodiments, the predetermined velocity is a critical velocityrequired for the metal particles to bond upon impacting the base. Insome embodiments, the critical velocity is greater than about 340 m/s.

In some embodiments, the method further comprises applying a laser beamat a predetermined power setting onto an area of the base where thestream of metal particles is impacting.

In another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises introducing a continuousfeed of metal wire onto a base surface and applying a beam at apredetermined power setting to an area where the metal wire contact thebase surface to form a porous three-dimensional structure and to form atleast one fixation feature that extends beyond a surface boundary of theporous three-dimensional structure. The porous three-dimensionalstructure is comprised of a plurality of unit cells. The fixationfeature is anchored to a first side of the porous three-dimensionalstructure and comprises a porous portion and a plurality of solidportions positioned on an outside surface of the porous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In some embodiments, the beam is an electron beam.

In some embodiments, the beam is a laser beam.

In yet another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises introducing a continuousfeed of polymer material embedded with metal elements onto a basesurface, applying heat to an area where the polymer material contactsthe base surface to form porous three-dimensional structure and to format least one fixation feature that extends beyond a surface boundary ofthe porous three-dimensional structure. The porous three-dimensionalstructure is comprised of a plurality of unit cells. The fixationfeature is anchored to a first side of the porous three-dimensionalstructure and comprises a porous portion and a plurality of solidportions positioned on an outside surface of the porous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In some embodiments, the method further includes scanning the porousthree-dimensional structure with a beam to burn off the polymermaterial.

In some embodiments, the heat is applied using a heating element. Insome embodiments, the heating element is part of a furnace system.

In another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises introducing a metal slurrythrough a nozzle onto a base surface to form a porous three-dimensionalstructure and at least one fixation feature that extends beyond asurface boundary of the porous three-dimensional structure. The porousthree-dimensional structure is comprised of a plurality of unit cells.The fixation feature is anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In yet another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises introducing successivelayers of molten metal onto a base surface to form a porousthree-dimensional structure and at least one fixation feature thatextends beyond a surface boundary of the porous three-dimensionalstructure. The porous three-dimensional structure is comprised of aplurality of unit cells. The fixation feature is anchored to a firstside of the porous three-dimensional structure and is comprised of aporous portion and a plurality of solid portions positioned on anoutside surface of the porous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises depositing and bindingsuccessive layers of metal powders with a binder material to form aporous three-dimensional structure and at least one fixation featurethat extends beyond a surface boundary of the porous three-dimensionalstructure. The porous three-dimensional structure is comprised of aplurality of unit cells. The fixation feature is anchored to a firstside of the porous three-dimensional structure and is comprised of aporous portion and a plurality of solid portions positioned on anoutside surface of the porous portion.

In some embodiments, the method further comprises providing a base andanchoring a second side of the porous three-dimensional structure to thebase.

In some embodiments, the method further includes sintering or meltingthe bound metal powder with a beam. In some embodiments, the beam is anelectron beam. In some embodiments, the beam is a laser beam.

In some embodiments, the method further includes sintering or meltingthe bound metal powder with a heating element.

In yet another aspect, a method for producing a porous three-dimensionalstructure is disclosed. The method comprises depositing droplets of ametal material onto a base surface and applying heat to an area wherethe metal material contacts the base surface to form a porousthree-dimensional structure and at least one fixation feature thatextends beyond a surface boundary of the porous three-dimensionalstructure. The porous three-dimensional structure is comprised of aplurality of unit cells. The fixation feature is anchored to a firstside of the porous three-dimensional structure and is comprised of aporous portion and a plurality of solid portions positioned on anoutside surface of the porous portion.

In some embodiments, the method further comprises anchoring a secondside of the porous three-dimensional structure to the base.

In some embodiments, the heat is applied with an electron beam.

In some embodiments, the heat is applied with a laser beam.

In some embodiments, the metal material is a metal slurry embedded withmetallic elements.

In some embodiments, the metal material is a metal powder.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the principles disclosed herein,and the advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view of an orthopaedic prosthetic component;

FIG. 2 is an elevation view of a fixation feature of the orthopaedicprosthetic component of FIG. 1;

FIG. 3 is a cross-sectional plan view of the fixation feature of FIG. 2taken along the line 3-3 in FIG. 2;

FIG. 4 is an elevation view of another fixation feature for theorthopaedic prosthetic component of FIG. 1;

FIG. 5 is a cross-sectional view of a portion of the fixation feature ofFIG. 4 taken along the line 5-5 in FIG. 4;

FIG. 6 is an elevation view of another fixation feature for theorthopaedic prosthetic component of FIG. 1;

FIG. 7 depicts a chart of the ratio of extraction to insertion force forvarious features, in accordance with various embodiments;

FIG. 8 depicts a flow chart of a method for manufacturing a porousthree-dimensional structure, in accordance with various embodiments; and

FIGS. 9A and 9B illustrate a cross sectional view of a fixation feature,in accordance with various embodiments.

DETAILED DESCRIPTION

This specification describes exemplary embodiments and applications ofthe disclosure. The disclosure, however, is not limited to theseexemplary embodiments and applications or to the manner in which theexemplary embodiments and applications operate or are described herein.Moreover, the figures may show simplified or partial views, and thedimensions of elements in the figures may be exaggerated or otherwisenot in proportion. In addition, as the terms “on,” “attached to,”“connected to,” “coupled to,” or similar words are used herein, oneelement (e.g., a material, a layer, a base, etc.) can be “on,” “attachedto,” “connected to,” or “coupled to” another element regardless ofwhether the one element is directly on, attached to, connected to, orcoupled to the other element, there are one or more intervening elementsbetween the one element and the other element, or the two elements areintegrated as a single piece. Also, unless the context dictatesotherwise, directions (e.g., above, below, top, bottom, side, up, down,under, over, upper, lower, horizontal, vertical, “x,” “y,” “z,” etc.),if provided, are relative and provided solely by way of example and forease of illustration and discussion and not by way of limitation. Inaddition, where reference is made to a list of elements (e.g., elementsa, b, c), such reference is intended to include any one of the listedelements by itself, any combination of less than all of the listedelements, and/or a combination of all of the listed elements. Sectiondivisions in the specification are for ease of review only and do notlimit any combination of elements discussed.

As used herein, “bonded to” or “bonding” denotes an attachment of metalto metal due to a variety of physicochemical mechanisms, including butnot limited to: metallic bonding, electrostatic attraction and/oradhesion forces.

Unless otherwise defined, scientific and technical terms used inconnection with the present teachings described herein shall have themeanings that are commonly understood by those of ordinary skill in theart.

The present disclosure relates to porous three-dimensional metallicstructures and methods for manufacturing them for medical applications.As described in greater detail below, the porous metallic structurespromote hard or soft tissue interlocks between prosthetic componentsimplanted in a patient's body and the patient's surrounding hard or softtissue. For example, when included on an orthopaedic prostheticcomponent configured to be implanted in a patient's body, the porousthree-dimensional metallic structure can be used to provide a porousouter layer of the orthopaedic prosthetic component to form a bonein-growth structure. Alternatively, the porous three-dimensionalmetallic structure can be used as an implant with the requiredstructural integrity to both fulfill the intended function of theimplant and to provide interconnected porosity for tissue interlock(e.g., bone in-growth) with the surrounding tissue.

In accordance with various embodiments, an orthopaedic prostheticcomponent is provided, the prosthetic component including a base, aporous three-dimensional structure, and at least one surface feature(hereinafter referred to as an engagement stud) extending past a surfaceboundary of the porous three-dimensional structure. The porous structurecan include a plurality of unit cells.

The orthopaedic implant/prosthetic component, by design, can be asurgical implant configured for implantation into a patient's bone. Forexample, as shown in FIG. 1, an orthopaedic prosthetic component 10 is atibial tray of a total knee arthroplasty prosthesis. The component 10includes a platform 12 having a stem 14 extending away from its lowersurface 16. The tibial stem 14 extends to a distal tip 18 and isconfigured to be implanted into a surgically-prepared proximal end of apatient's tibia (not shown). The platform 12 also has an upper surface20 positioned opposite the lower surface 16 and a curved outer wall 22that extends between the surfaces 16, 20. In the illustrativeembodiment, the curved outer wall 22 is shaped to correspond to theouter edge of a surgically-prepared surface on the proximal end of thepatient's tibia. The platform 12 also has various engagement features(not shown) attached to the upper surface 20, which are configured toengage an insert or bearing of the total knee arthroplasty prosthesis.Exemplary engagement features, as well as exemplary other components ofthe knee arthroplasty prosthesis, are shown and described in U.S. Pat.No. 8,470,047, which is expressly incorporated herein by reference.

The platform 12 of the component 10 is constructed with a biocompatiblemetal, such as a cobalt chrome or titanium alloy, although othermaterials may also be used. As shown in FIG. 1, the component 10includes a three-dimensional ingrowth body 100, which is attached to thelower surface 16 of the platform 12 such that the platform 12 provides abase for the ingrowth body 100. The ingrowth body 100 includes a porousthree-dimensional structure 110 that is configured to promote boneingrowth for permanent fixation, as described in greater detail below.

In the illustrative embodiment, the ingrowth body 100 includes a layeror plate 102 attached to the lower surface 16 of the platform 12 and anumber of pegs 104 that extend outwardly from the plate 102. Theingrowth body 100 is also attached to the stem 14, which extendsoutwardly through the layer 102 to its distal tip 18. It should beappreciated that although a tibial prosthetic component is shown, thevarious porous structures described herein (including engagement studstructures described herein) can be incorporated into variousorthopaedic implant designs such that the design of the implant will notimpact the ability to use any of the various embodiments of engagementstuds discussed herein. For example, the porous structures describedherein may be included in a femoral prosthetic component similar to thefemoral component shown in U.S. Pat. No. 8,470,047 or on a patellacomponent shaped to engage the femoral prosthetic component. The porousstructures may also be included in other orthopaedic implant designs,including prosthetic components for use in a hip or shoulderarthroplasty surgery.

It should be noted, for the preceding and going forward, that a base canbe any type of structure capable of, for example, contacting,supporting, connecting to or with, or anchoring to or with components ofvarious embodiments herein. Bases can include, for example, a metal ornon-metal platform, a metal or non-metal tray, a metal or non-metalbaseplate, a metal or non-metal structure that sits on a tray, and soon.

Referring now to FIG. 2, one fixation peg 104 is shown in greaterdetail. In the illustrative embodiment, each of the pegs 104 has anidentical configuration. The ingrowth body 100 (and hence each peg 104)includes a porous three-dimensional structure 110 that includes aplurality of unit cells 120, each made up multiple struts 125. Theplurality of unit cells 120 are provided in repeating patterns to formthe structure 110, which has an outer surface boundary 130. The unitcells 120 define pores or voids that permit bone ingrowth after theorthopaedic prosthetic component 10 is implanted in the patient's bone,thereby promoting fixation between the component 10 and the surroundingbone tissue.

Each fixation peg 104 extends from a proximal end 132 attached to thelayer 102 of the ingrowth body 100 to a distal end 134. In theillustrative embodiment, the fixation pegs 104 and the layer 102 areformed as a single monolithic porous component. It should be appreciatedthat in other embodiments the layer 102 may be formed separately fromone or more of the fixation pegs 104 and later assembled with thepeg(s). It should also be appreciated that one or more of the fixationpegs may be attached directed to the platform 16 and extend through thelayer 102.

Each fixation peg 104 extends along a longitudinal axis 140 between theends 132, 134. As shown in the cross-section of FIG. 3, the outersurface boundary 130 of each peg 104 extends circumferentially aroundthe longitudinal axis 140. In the illustrative embodiment, the outersurface boundary 130 includes a convex section 142 and a number ofconcave sections 144 that define grooves or channels 148 within theconvex section 142. The fixation peg 104 includes a plurality of plates150, which are attached at the surface boundary 130 within the groovesand are configured to reduce bone abrasion, as described in greaterdetail below. In other embodiments, the profile of the surface boundarymay be more or less uneven than the illustrative embodiment to receiveplates of other designs.

In the illustrative embodiment, each groove 148 has a scallop-shape thatis tapered. Each of the plurality of plates 150 occupies a respectivescallop. Each of the grooves 148 comprises a distal region and proximalregion, wherein a portion of the distal region is larger than theproximal region. Alternatively, one or more of the plurality of groovescan comprise a distal region and proximal region, wherein the distalregion is smaller than the proximal region.

The plates 150 are arranged circumferentially on the surface boundary130 of the porous three-dimensional structure 110 of each fixation peg104. In the illustrative embodiment, the plates 150 are spaced apartfrom one another by the porous three-dimensional structure 110.Returning to FIG. 2, each plate 150 has a tapered body 152 that extendsalong the longitudinal axis 140 from a proximal end 154 to a distal end156. The tapered body 152 of each plate 150 has an outer wall 158 thatfaces away from the porous three-dimensional structure 110. In theillustrative embodiment, the outer wall 158 is devoid of any openings,and the tapered body 152 is a solid material without any through-holes.It should be appreciated that in other embodiments portions of the outerwall 158 may include openings or through-holes depending on theconfiguration of the plate and the orthopaedic application.

Each tapered body 152 comprises a distal region 160 including the distalend 156 and a proximal region 162 including the proximal end 154,wherein the distal region includes a portion that is larger than theproximal region. Alternatively, the occupying solid portions cancomprise a distal region and proximal region, and the distal regionincludes a portion that is smaller than the proximal region. As shown inFIG. 2, each tapered body 152 has a width 164 in the proximal region 162(illustratively at the proximal end 154) and tapers to another, largerwidth 166 in the distal region 160 (but illustratively between the ends154, 156).

The outer wall 158 of each tapered body 152 includes a concave surface170 that defines a channel 172 that is tapered to correspond to thetapering of the body 152. Each channel 172 has an open distal end tofacilitate insertion of the peg 104 into a patient's bone. It should beappreciated that in other embodiments channels 172 may have differentconfigurations. As shown in FIG. 2, the distal end 156 of each plate 150is positioned proximal of the distal tip 134 of each fixation peg 104such that the plates are positioned between the distal tip 156 and theplatform 12 of the orthopaedic prosthetic component. It should beappreciated that in other embodiments the distal end of the plate may bepositioned at the distal tip such that they are aligned in a distalplane.

In various embodiments, and as stated above, the solid material can be ametal or non-metal, and the types of metal can include, but are notlimited to, titanium, titanium alloys, stainless steel, cobalt chromealloys, tantalum or niobium. Non-metal examples include, for examples,ceramic materials (e.g., titanium nitride) and carbon materials (e.g.,silicon carbide).

By providing a combination of solid components and porous components,the fixation pegs are configured to reduce bone abrasion and increasefixation strength, while still having the porous structure necessary forpromoting bone in-growth and also allowing, as needed, for ease ofrevision (e.g., cutting through the pegs).

As described above, each fixation peg 104 has a porous structure withsolid portions positioned at the surface boundary of the porousstructure. It should be appreciated that in other embodiments thefixation peg or feature may have a solid core. For example, as shown inFIG. 9A, a fixation peg 910 has a solid core embedded therein. In FIG.9A, the fixation feature 910 comprises a porous portion 920 and aplurality of solid plates 930 (or a plurality of solid portions 930).The porous portion 920 furthers include a core 940 of solid material. InFIG. 9B, the porous portion 930 is substantially replaced by a solidcore 950. Providing such a solid core, in either case, may potentiallyprovide additional strength to the fixation feature overall to withstandthe stress of being embedded in tissue such as bone or for cleaningpurposes as needed.

Referring now to FIGS. 4-6, other examples of fixation features areillustrated, in accordance with various embodiments. In FIGS. 4 and 5, afixation feature 410 (illustratively another fixation peg) is provided,with the feature 410 comprising a porous three-dimensional structure orportion 420 and at least one solid plate or portion 430. In variousembodiments, and as illustrated in FIG. 4, the fixation feature 410 cancomprise a plurality of solid portions 430. At least one of theplurality of solid portions can be attached to a surface of the porousportion 420. In FIG. 4, each of the plurality of solid portions 430 isattached to a porous portion 420.

As shown in FIG. 5, each of the plurality of solid portions 430 tapersin the distal direction such that the thickness of each respective solidportion is less than the solid portion immediately proximal. In otherwords, as shown in FIG. 5, each solid portion 430 has a thickness 432 atits distal end 434 and another, greater thickness 436 proximal of thedistal end 434 (illustratively between the distal end 434 and theproximal end 438 of the portion 430). This representative thicknessdifference between succeeding solid portions presents an overalltapering effect across the solid portions take together, as illustrated,for example, by the successive narrowing of solid portions 430 asfixation feature 410 proceeds distally.

As shown in FIGS. 4-5, each of the solid plates or portions 430 extendcircumferentially around the porous portion 420. Adjacent portions 430of the plurality of portions 430 are spaced apart from each other on theporous portion 420 in a proximal-distal direction.

By providing a design similar to that illustrated, for example, in FIGS.4 and 5, the solid portions can reduce bone abrasion and increase hoopstresses in the bone. However, with the porous portion, the fixationfeature provides regions for bone in-growth and ease of revision.Moreover, by providing designs with a tapering solid portion orplurality of solid portions, the most distal portion of the solidportion may provide a cutting path into the bone that would not disturbbone needed to secure subsequent regions of the solid portion (orsubsequent solid portions of the plurality of solid portions).

Referring now to FIG. 6, another fixation feature (hereinafter feature610) is provided. The fixation feature 610 extends from a layer of aporous three-dimensional structure 660 attached to the platform of thetibial prosthetic component. The fixation feature 610, like the pegs andfeatures of FIGS. 1-5, is configured to engage a patient's bone. Similarto the pegs 104 described above, the fixation feature 610 may be part ofa porous three-dimensional structure attached to a solid platform. Insuch embodiments, a second side 680 of porous three-dimensionalstructure 660 may be anchored to the platform. Additionally, thefixation feature 610 may be one of a number of fixation features 610. Itshould also be appreciated that the porous structure 660 can be a solid,or substantially solid, structure. As shown in FIG. 6, each fixationfeature 610 includes a porous portion 620 that is anchored to a firstside of the layer of structure 660. The porous portion 620 has aplurality of voids or openings that extend through the porous portion620 and open into an interior 655.

The fixation feature 610 extends to a distal tip 690, and a solidportion 630 is positioned at the distal tip 690 on an outside surface640 of the porous portion 620. In accordance with various embodiments,and as illustrated for example in FIG. 6, the solid portion includes anumber of plates or barbs 695 that are positioned substantiallyperpendicular to the surface boundary of the porous portion 620. Eachbarb 695 illustratively tapers in the distal direction (e.g., towardsdistal tip 690 of fixation feature 610). As shown in FIG. 6, thethickness of each respective barb is less than the barb immediatelyproximal, and this representative thickness difference betweensucceeding barbs presents an overall tapering effect across the solidportion 630 by the narrowing of solid portion 630 as fixation feature610 proceeds distally towards tip region 690. Thus, the at least onesolid portion can taper in the distal direction. In other embodiments,the solid portion 630 may not taper. It should also be appreciated thatin other embodiments the solid portion 630 may include additional orfewer barbs 695. As illustrated in FIG. 6 for example, the solid portion630 surrounds the porous portion 620.

The fixation feature 610 also includes an elongated slot 670 thatextends from an opening 696 at the distal tip 690. As shown in FIG. 6,the elongated slot 670 extends through the interior 655 of the porousportion 620. The solid portion 630 illustratively includes an insidesurface 675 that defines the slot 670. In other embodiments, theelongated slot 670 may be defined by a solid portion separate from thebarbs 695. It should also be appreciated that in other embodiments theinside surface 675 may be porous or partially porous.

In accordance with various embodiments, the fixation feature can furthercomprise a length and a width, wherein the length is greater than thewidth (as illustrated in FIG. 6). The fixation feature can furthercomprise a length and a width, wherein the width is greater than thelength.

As stated above, in various embodiments, the fixation feature cancomprise a plurality of solid portions. Each of the plurality of solidportions can surround the porous portion. Each of the plurality of solidportions can taper in the distal direction. Each of the plurality ofsolid portions can include at least one barb, wherein the at least onebarb tapers in the distal direction.

By providing a fixation feature with a slot as illustrated, for example,in FIG. 6, the fixation feature can deflect during fixation featureinsertion to help prevent bone abrasion. The porous portion assists inproviding the low modulus necessary for deflection of the fixationfeatures, or more specifically the barbs on the solid portion, whilealso allowing for sufficient bone in-growth and ease of revision. Itshould also be noted that, while FIG. 6 illustrates a single slot, aplurality of slots could be used (e.g., 3 to 4 slots) to minimize anydirectionality of the slotted design.

Referring now to FIG. 7, a chart 700 is provided to showextraction/insertion force ratio results from fixation feature pull-outtesting for various designs. Each fixation feature was inserted andextracted from bone, with ratios calculated for each tested fixationfeature indicative of the force of insertion versus the force ofextraction. As such, high ratios would indicate any of a number ofadvantageous features for a given fixation feature including, forexample, ease of fixation feature insertion into tissue and resistanceto extraction, which would be indicative of fixation feature stabilityin the tissue (e.g., bone).

The three highlighted results are examples described by the conceptsillustrated in FIGS. 2 to 6 and described in detail above. The result710 illustrates the performance of a peg 104 (see FIGS. 2-3), and theresult 712 illustrates the performance of the fixation feature 410 (seeFIGS. 4-5), while the result 714 illustrates the performance of thefixation feature 610 (see FIG. 6). The three highlighted conceptsperformed as well as other pegs tested, which included devices similarto those with clinical usage. The results reinforce the advantageousnature of the various embodiments herein, which provide additionalstability (e.g., as illustrated by the extraction/insertion force ratiosof the embodiments disclosed herein).

Manufacturing Processes

The porous three-dimensional metallic structures disclosed above can bemade using a variety of different metal component manufacturingtechniques, including but not limited to: Casting Processes (castingprocesses involve pouring molten metal into a mold cavity where, oncesolid, the metal takes on the shape of the cavity. Examples include,expendable mold casting, permanent mold casting, and powder compactionmetallurgy), Deformation Processes (deformation processes include metalforming and sheet metalworking processes which involve the use of a toolthat applies mechanical stresses to metal which exceed the yield stressof the metal), Material Removal Processes (these processes remove extramaterial from the workpiece in order to achieve the desired shape.Examples of material removal processes include, tool machining andabrasive machining), and Additive Manufacturing Processes (theseprocesses involve the use of digital 3D design data to build up a metalcomponent up in layers by depositing successive layers of material).Additive Manufacturing Processes can include, only by way of example,powder bed fusion printing (e.g., melting and sintering), cold spray 3Dprinting, wire feed 3D printing, fused deposition 3D printing, extrusion3D printing, liquid metal 3D printing, stereolithography 3D printing,binder jetting 3D printing, material jetting 3D printing, and so on. Itshould be appreciated, however, that additive manufacturing processesoffer some unique advantages over the other metal componentmanufacturing techniques with respect to the manufacture of porousthree-dimensional metallic structures (disclosed above) due to thecomplexities of the geometries and structural elements of the unit cellswhich comprise those types of structures.

In accordance with various embodiments, a method for producing anorthopaedic implant is provided, for example, by method 800 illustratedin FIG. 8. The method can comprise depositing and scanning successivelayers of metal powders with a beam to form a porous three-dimensionalstructure. The porous three-dimensional structure can comprise aplurality of unit cells and the depositing and scanning can form atleast one fixation feature that extends beyond a surface boundary of theporous three-dimensional structure. The at least one fixation featurecan be anchored to a first side of the porous three-dimensionalstructure and comprises a porous portion having an interior, at leastone solid portion, and at least one slot at least partially located onthe interior of the porous portion. The beam (or scanning beam) can bean electron beam. The beam (or scanning beam) can be a laser beam.

As provided in FIG. 8, step 810 includes depositing a layer of metalpowder. Step 820 includes scanning a layer of metal powder. As providedin step 830, the steps 810 and 820 are repeated until a porousthree-dimensional structure is formed comprising a plurality of unitcells, and at least one fixation feature is formed that extends beyond asurface boundary of the porous-three-dimensional structure, wherein theat least one fixation feature is anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion.

Regarding the various methods described herein, the metal powders can besintered to form the porous three-dimensional structure. Alternatively,the metal powders can be melted to form the porous three-dimensionalstructure. The successive layers of metal powders can be deposited ontoa solid base (see above for discussion regarding base). In variousembodiments, the types of metal powders that can be used include, butare not limited to, titanium, titanium alloys, stainless steel, cobaltchrome alloys, tantalum or niobium powders. In various embodiments, asecond side of the porous three-dimensional structure can be anchored tothe base.

In accordance with various embodiments, a method for producing anorthopaedic implant is provided. The method can comprise depositing andscanning successive layers of metal powders to form a porousthree-dimensional structure comprising a plurality of unit cells and toform at least one fixation feature that extends beyond a surfaceboundary of the porous-three-dimensional structure. The at least onefixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,providing a base, and anchoring a second side of the porousthree-dimensional structure to the base.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can comprisedepositing and scanning successive layers of metal powders with a beamto form a porous three-dimensional structure comprising a plurality ofunit cells and to form at least one fixation feature that extends beyonda surface boundary of the porous-three-dimensional structure. The atleast one fixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,providing a base, and anchoring a second side of the porousthree-dimensional structure to the base. The beam can be an electronbeam. The beam can be a laser beam. In various embodiments, the metalpowders are sintered to form the porous three-dimensional structure. Invarious embodiments, the metal powders are melted to form the porousthree-dimensional structure. In various embodiments, the successivelayers of metal powders are deposited onto a solid base.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseapplying a stream of metal particles at a predetermined velocity onto abase to form a porous three-dimensional structure comprising a pluralityof unit cells and to form at least one fixation feature that extendsbeyond a surface boundary of the porous-three-dimensional structure. Theat least one fixation feature can be anchored to a first side of theporous three-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,anchoring a second side of the porous three-dimensional structure to thebase. The predetermined velocity can be a critical velocity required forthe metal particles to bond upon impacting the base. The criticalvelocity can be greater than 340 m/s. The method can further includeapplying a laser at a predetermined power setting onto an area of thebase where the stream of metal particles is impacting. In variousembodiments, the types of metal particles that can be used include, butare not limited to, titanium, titanium alloys, stainless steel, cobaltchrome alloys, tantalum or niobium particles.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseintroducing a continuous feed of metal wire onto a base surface andapplying a beam at a predetermined power setting to an area where themetal wire contacts the base surface to form a porous three-dimensionalstructure comprising a plurality of unit cells and to form at least onefixation feature that extends beyond a surface boundary of theporous-three-dimensional structure. The at least one fixation featurecan be anchored to a first side of the porous three-dimensionalstructure and comprises a porous portion and a plurality of solidportions positioned on an outside surface of the porous portion. Themethod can further comprise, in various embodiments, anchoring a secondside of the porous three-dimensional structure to the base. The beam canbe an electron beam. The beam can be a laser beam. In variousembodiments, the types of metal wire that can be used include, but arenot limited to, titanium, titanium alloys, stainless steel, cobaltchrome alloys, tantalum or niobium wire.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseintroducing a continuous feed of a polymer material embedded with ametal element onto a base surface and applying heat to an area where thepolymer material contacts the base surface to form a porousthree-dimensional structure comprising a plurality of unit cells and toform at least one fixation feature that extends beyond a surfaceboundary of the porous-three-dimensional structure. The at least onefixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,anchoring a second side of the porous three-dimensional structure to thebase. In various embodiments, the continuous feed of polymer materialcan be supplied through a heated nozzle thus eliminating the need forapplying heat to the area where the polymer material contacts the basesurface to form the porous three-dimensional structures. In variousembodiments, the types of metal elements that can be used to embed thepolymer material can include, but are not limited to, titanium, titaniumalloys, stainless steel, cobalt chrome alloys, tantalum and niobium.

The method can further include scanning the porous three-dimensionalstructure with a beam to burn off the polymer material. The beam (orscanning beam) can be an electron beam. The beam (or scanning beam) canbe a laser beam.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseintroducing a metal slurry through a nozzle onto a base surface to forma porous three-dimensional structure comprising a plurality of unitcells and to form at least one fixation feature that extends beyond asurface boundary of the porous-three-dimensional structure. The at leastone fixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,anchoring a second side of the porous three-dimensional structure to thebase. In various embodiments, the nozzle is heated at a temperaturerequired to bond the metallic elements of the metal slurry to the basesurface. In various embodiments, the metal slurry is an aqueoussuspension containing metal particles along with one or more additive(liquid or solid) to improve the performance of the manufacturingprocess or the porous three-dimensional structure. In variousembodiments, the metal slurry is an organic solvent suspensioncontaining metal particles along with one or more additive (liquid orsolid) to improve the performance of the manufacturing process or theporous three-dimensional structure. In various embodiments, the types ofmetal particles that can be utilized in the metal slurry include, butare not limited to, titanium, titanium alloys, stainless steel, cobaltchrome alloys, tantalum or niobium particles.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseintroducing successive layers of molten metal onto a base surface toform a porous three-dimensional structure comprising a plurality of unitcells and to form at least one fixation feature that extends beyond asurface boundary of the porous-three-dimensional structure. The at leastone fixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,anchoring a second side of the porous three-dimensional structure to thebase. The molten metal can be introduced as a continuous stream onto thebase surface. The molten metal can be introduced as a stream of discretemolten metal droplets onto the base surface. In various embodiments, thetypes of molten metals that can be used include, but are not limited to,titanium, titanium alloys, stainless steel, cobalt chrome alloys,tantalum or niobium.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can compriseapplying and photoactivating successive layers of photosensitive polymerembedded with metal elements onto a base surface to form a porousthree-dimensional structure comprising a plurality of unit cells and toform at least one fixation feature that extends beyond a surfaceboundary of the porous-three-dimensional structure. The at least onefixation feature can be anchored to a first side of the porousthree-dimensional structure and comprises a porous portion and aplurality of solid portions positioned on an outside surface of theporous portion. The method can further comprise, in various embodiments,anchoring a second side of the porous three-dimensional structure to thebase. In various embodiments, the types of metal elements that can beused to embed the polymer material can include, but are not limited to,titanium, titanium alloys, stainless steel, cobalt chrome alloys,tantalum or niobium.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can comprisedepositing and binding successive layers of metal powders with a bindermaterial to form a porous three-dimensional structure comprising aplurality of unit cells and to form at least one fixation feature thatextends beyond a surface boundary of the porous-three-dimensionalstructure. The at least one fixation feature can be anchored to a firstside of the porous three-dimensional structure and comprises a porousportion and a plurality of solid portions positioned on an outsidesurface of the porous portion. The method can further comprise, invarious embodiments, a base and anchoring a second side of the porousthree-dimensional structure to the base. In various embodiments, thetypes of metal powders that can be used include, but are not limited to,titanium, titanium alloys, stainless steel, cobalt chrome alloys,tantalum or niobium powders.

The method can further include sintering or melting the bound metalpowder with a beam. The beam can be an electron beam. The beam can be alaser beam. The method can further include sintering or melting thebound metal powder with a heating element, where the beam is an electronbeam, or the beam is a laser beam.

In accordance with various embodiments, a method for producing a porousthree-dimensional structure is provided. The method can comprisedepositing droplets of a metal material onto a base surface, andapplying heat to an area where the metal material contacts the basesurface to form a porous three-dimensional structure comprising aplurality of unit cells and to form at least one fixation feature thatextends beyond a surface boundary of the porous-three-dimensionalstructure. The at least one fixation feature can be anchored to a firstside of the porous three-dimensional structure and comprises a porousportion and a plurality of solid portions positioned on an outsidesurface of the porous portion. The method can further comprise, invarious embodiments, anchoring a second side of the porousthree-dimensional structure to the base. The heat can be applied with abeam, wherein the beam is an electron beam. The heat can be applied witha beam, wherein the beam is a laser beam. The metal material can be ametal slurry embedded with metallic elements. The metal material can bea metal powder. In various embodiments, the types of metal materialsthat can be used include, but are not limited to, titanium, titaniumalloys, stainless steel, cobalt chrome alloys, tantalum or niobium.

Although specific embodiments and applications of the same have beendescribed in this specification, these embodiments and applications areexemplary only, and many variations are possible.

While the present teachings are described in conjunction with variousembodiments, it is not intended that the present teachings be limited tosuch embodiments. On the contrary, the present teachings encompassvarious alternatives, modifications, and equivalents, as will beappreciated by those of skill in the art.

Further, in describing various embodiments, the specification may havepresented a method and/or process as a particular sequence of steps.However, to the extent that the method or process does not rely on theparticular order of steps set forth herein, the method or process shouldnot be limited to the particular sequence of steps described. As one ofordinary skill in the art would appreciate, other sequences of steps maybe possible. Therefore, the particular order of the steps set forth inthe specification should not be construed as limitations on the claims.In addition, the claims directed to the method and/or process should notbe limited to the performance of their steps in the order written, andone skilled in the art can readily appreciate that the sequences may bevaried and still remain within the spirit and scope of the variousembodiments.

Although specific embodiments and applications of the same have beendescribed in this specification, these embodiments and applications areexemplary only, and many variations are possible.

While the present teachings are described in conjunction with variousembodiments, it is not intended that the present teachings be limited tosuch embodiments. On the contrary, the present teachings encompassvarious alternatives, modifications, and equivalents, as will beappreciated by those of skill in the art.

Further, in describing various embodiments, the specification may havepresented a method and/or process as a particular sequence of steps.However, to the extent that the method or process does not rely on theparticular order of steps set forth herein, the method or process shouldnot be limited to the particular sequence of steps described. As one ofordinary skill in the art would appreciate, other sequences of steps maybe possible. Therefore, the particular order of the steps set forth inthe specification should not be construed as limitations on the claims.In addition, the claims directed to the method and/or process should notbe limited to the performance of their steps in the order written, andone skilled in the art can readily appreciate that the sequences may bevaried and still remain within the spirit and scope of the variousembodiments.

What is claimed:
 1. A method for implanting an orthopaedic prostheticcomponent, the method comprising the steps of: inserting a fixation peginto a bone of a human body to facilitate bone ingrowth into a porousthree-dimensional structure of the fixation peg, wherein the porousthree-dimensional structure has an outer surface boundary, wherein thefixation peg includes a plurality of plates attached to the porousthree-dimensional structure at the outer surface boundary, each plateincluding a body having an outer wall that faces away from the porousthree-dimensional structure, the outer wall defining a channel that hasan open distal end to facilitate insertion of the fixation peg into thebone during the implanting step.
 2. The method of claim 1, wherein theinserting step further comprises the step of inserting a base into thehuman body, wherein the fixation peg extends from the base.
 3. Themethod of claim 2, wherein the fixation peg extends away from theplatform to a distal tip, and a respective distal end of each of theplates is position proximal of the distal tip of the fixation peg. 4.The method of claim 3, wherein the plurality of plates are positionedbetween the distal tip of the fixation peg and the platform.
 5. Themethod of claim 4, wherein the distal tip of the fixation peg includes alongitudinal slot.
 6. The method of claim 2, wherein the bone is atibia, the base includes a tibial platform, and the method furthercomprising the step of inserting a tibial stem of the orthopaedicprosthetic component into a surgically prepared proximal end of thetibia, wherein the tibial stem extends away from the lower surface. 7.The method of claim 6, wherein the inserting step comprises receiving atibial insert at the tibial platform.
 8. The orthopaedic prostheticcomponent of claim 7, wherein the inserting step facilitates boneingrowth into a porous three-dimensional structure that is attached to adistal surface of the tibial platform, and the fixation peg extends awayfrom the distal surface.
 9. The method of claim 8, wherein the tibialstem extends outwardly from the three-dimensional structure that isattached to the distal surface of the tibial platform, and the fixationpeg extends outwardly from the porous three-dimensional structure thatis attached to the distal surface of the tibial platform.
 10. The methodof claim 6, wherein the tibial platform has a curved outer wall shapedto correspond, during the inserting step, to an outer edge of asurgically prepared surface on the proximal end of the tibia during. 11.The method of claim 1, wherein the fixation peg has a solid core duringthe inserting step.
 12. The method of claim 1, wherein each plateincludes a tapered body such that the channel is a tapered channel,wherein the tapered body has an outer wall that faces away from theporous three-dimensional structure and is devoid of any openings. 13.The method of claim 12, wherein the outer wall of each plate includes aconcave surface that defines the tapered channel.
 14. The method ofclaim 13, wherein the tapered body of each plate extends longitudinallyalong the porous three-dimensional structure, the tapered body of eachplate extends from a proximal end to a distal end, and the tapered bodyof each plate has a first width at the proximal end and a second widthgreater than the first width between the proximal end and the distalend.
 15. The method of claim 12, wherein: the tapered body of each plateextends from a proximal end to a distal end, and the tapered body ofeach plate has a first thickness at the distal end and a secondthickness greater than the first thickness between the proximal end andthe distal end.
 16. The method of claim 1, wherein adjacent plates ofthe plurality of plates are spaced apart circumferentially from eachother on the porous three-dimensional structure.
 17. The orthopaedicprosthetic component of claim 1, wherein adjacent plates of theplurality of plates are spaced apart from each other on the porousthree-dimensional structure in a proximal-distal direction.